fix(agent-config): use deserialize_optional_string for org_uuid

A UUID is hex + dashes; there is no legitimate numeric form a user
would supply. The previous deserializer (deserialize_string_or_int)
was a carry-over from the bottlecap copy, where it appears to have
been copy-pasted from the env/service/version pattern. Tightening to
deserialize_optional_string fail-fasts on misconfiguration instead of
silently coercing.

Author: duncanista

crates/datadog-agent-config/src/sources/env.rs

@@ -38,9 +38,8 @@ pub struct EnvConfig {
     /// @env `DD_ORG_UUID`
     ///
     /// The Datadog organization UUID. When set, enables delegated auth so the
-    /// agent can submit telemetry without a long-lived API key. Accepts a
-    /// string or numeric form for backwards compatibility.
-    #[serde(deserialize_with = "deserialize_string_or_int")]
+    /// agent can submit telemetry without a long-lived API key.
+    #[serde(deserialize_with = "deserialize_optional_string")]
     pub org_uuid: Option<String>,
     /// @env `DD_LOG_LEVEL`
     ///

crates/datadog-agent-config/src/sources/yaml.rs

@@ -31,9 +31,8 @@ pub struct YamlConfig {
     pub api_key: Option<String>,
     /// YAML key: `org_uuid`. Datadog organization UUID. When set, enables
     /// delegated auth so the agent can submit telemetry without a long-lived
-    /// API key. Accepts a string or numeric form for backwards compatibility.
-    /// Merges into the resolved config field `dd_org_uuid`.
-    #[serde(deserialize_with = "deserialize_string_or_int")]
+    /// API key. Merges into the resolved config field `dd_org_uuid`.
+    #[serde(deserialize_with = "deserialize_optional_string")]
     pub org_uuid: Option<String>,
     #[serde(deserialize_with = "deserialize_with_default")]
     pub log_level: Option<LogLevel>,